[R] expand.grid function
Satoshi Takahama
brown_emu at yahoo.com
Tue Dec 25 10:46:12 CET 2007
Hi Derek,
I love this function as well. If 'mat' is your matrix,
> (mat <- matrix(1:15,ncol=3))
[,1] [,2] [,3]
[1,] 1 6 11
[2,] 2 7 12
[3,] 3 8 13
[4,] 4 9 14
[5,] 5 10 15
how about
> expandedDF <- do.call(`expand.grid`,as.data.frame(mat))
> head(expandedDF)
V1 V2 V3
1 1 6 11
2 2 6 11
3 3 6 11
4 4 6 11
5 5 6 11
6 1 7 11
[...]
(the function name can be in backticks, single or double quotes, or passed with no quotes). Hope this helps,
ST
----- Original Message ----
From: dxc13 <dxc13 at health.state.ny.us>
To: r-help at r-project.org
Sent: Sunday, December 23, 2007 7:59:49 PM
Subject: [R] expand.grid function
useR's,
I have used expand.grid() several times and like the results it gives
me. I
am now trying something with it that I have not been able to get to
work.
For any n column matrix I would like to run this function on those n
columns
and store the results.
For example, if my matrix has 1 column then this is just expand.grid(x
=
column1). If my matrix has two columns, then I want expand.grid(x =
column1, y = column2), and so on for any number of columns...
In a program I am writing, the user can specify any matrix. Does
anyone
know of a way for R to calculate this based on what the input matrix
is?
e.g. if this user gives a 3 column matrix, I want to be able to perform
expand.grid() on these 3 columns without having to hard code it b/c I
want
to have this small function embedded in my code and the results stored
as a
variable.
If this isn't clear, I can try to be more detailed. Thank you for any
thoughts.
Derek
--
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http://www.nabble.com/expand.grid-function-tp14484403p14484403.html
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